Fuel and lubricant additives, their preparation and fuel or lubricant compositions containing these additives

ABSTRACT

Fuel or lubricant additives based on reaction products of an ethylenically unsaturated poly-1-alkene derived from one or more 1-alkenes of 3 to 24 carbon atoms and from 0 to 50% by weight of ethene, processes for their preparation and fuel or lubricant compositions containing these additives are described.

This application is a 371 PCT/EP 95/01249 filed Apr. 5, 1995.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to fuel and lubricant additives based onlong-chain hydrocarbon radicals having a polar terminal group, ahalogen-free, one-stage process for the preparation of these additives,in which polar reactants are subjected to a free radical additionreaction at the double bond of a long-chain olefin, and fuel andlubricant compositions which contain these additives.

2. Discussion of the Background

Carburettors and intake systems of gasoline engines as well as injectionsystems for metering fuel in gasoline and diesel engines areincreasingly being contaminated by impurities which are caused by dustparticles from the air, uncombusted hydrocarbon residues from thecombustion chamber and crank case vent gases passed into thecarburettor.

These residues shift the air/fuel ratio during idling and in the lowerpart-load range so that the mixture becomes richer, the combustionbecomes more incomplete and in turn the proportions of uncombusted orpartly combusted hydrocarbons in the exhaust gas becomes larger and thegasoline consumption rises.

It is known that, in order to avoid these disadvantages, fuel additivesare used for keeping valves and carburettors or injection systems clean(cf. for example: M. Rossenbeck in Katalysatoren, Tenside,Mineraloladditive, ed. J. Falbe and U. Hasserodt, page 223, G. ThiemeVerlag, Stuttgart 1978).

Depending on the mode of action as well as on the preferred place ofaction of such detergent additives, a distinction is made today betweentwo generations.

The first generation of additives was capable only of preventing theformation of deposits in the intake system but not of removing existingdeposits, whereas the modern additives of the second generation canachieve both (keep-clean and clean-up effect), and can do so inparticular because of their excellent heat stability in zones atrelatively high temperature, ie. in the intake valves.

The molecular structural principle of these additives which act asdetergents can be stated in general to be a linkage of polar structureswith mostly high molecular weight, nonpolar or oleophilic radicals.

Members of the second generation of additives are often products basedon polyisobutene in the nonpolar moiety. Here too, additives of thepolyisobutylamine type are particularly noteworthy.

Such detergents are obtained, starting from polyisobutenes, essentiallyby two multistage synthesis processes.

The first involves chlorination of the polymeric parent structure,followed by nucleophilic substitution of the polymeric parent structureby amines or, preferably, ammonia. A disadvantage of this process, apartfrom the two-stage nature of the synthesis, is the use of chlorine whichresults in the occurrence of chlorine- or chloride-containing products,which is no longer desirable today.

In the second process, polyisobutylamines are obtained frompolyisobutene by hydroformylation, followed by reductive amination, ie.once again a two-stage process which also requires an appropriateinfrastructure.

Simple, one-stage, chlorine-free synthesis processes for detergents anddispersants or compounds which combine both property profiles, which canbe carried out in standard apparatuses, are therefore of particulartechnical and economic interest.

GB-A-1,383,423 discloses a method for the preparation of alkylpolyamineswhich can be used as carburettor detergents. Here, an α-olefin of atleast 15 carbon atoms is reacted with a polyamine in the presence of afree radical initiator. The α-olefins used are particularly preferablypolyisobutylenes.

EP-B-0 342 792 describes a process for the preparation of a polybutenehaving a thioether function, in which an organic thiol is reacted with aliquid polybutene which has one carbon-carbon double bond per moleculeand a number average molecular weight of from 200 to 10,000 underconditions in which free radicals are produced.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide compounds which aresuitable as fuel or lubricant additives and are obtainable by aone-stage chlorine-free synthesis which is not technically complicated.

We have found that this object is achieved by fuel or lubricantadditives which are obtainable by reacting an ethylenically unsaturatedpoly-1-alkene, derived from one or more 1-alkenes of 3 to 24, preferably3 to 10 and particularly preferably 3 to 6, carbon atoms and from 0 to50% by weight of ethene, with

a) a compound of the general formula I ##STR1## and/or b) a compound ofthe general formula II ##STR2## where X is O or NR⁷,

R¹ is CN, COOH, C(O)OR⁹, C(O)O(O)CR⁶, CONR⁶ R⁷, C(O)R⁹, C(S)R⁹, CHO,CH(NR⁶ R⁷)R⁶, SCR⁶ R⁷ R⁸, NR⁷ R⁹ or OR⁶,

R² and R³ are identical or different and are each R¹, hydrogen or anorganic radical differing therefrom,

R⁴ and R⁵ are identical or different and are each hydrogen, OR⁹, NR⁷ R⁸or an unsubstituted or substituted (cyclo)alkyl radical or aryl radical,

R⁶, R⁷ and R⁸ are identical or different and are each hydrogen or anorganic radical and

R⁹ is an organic radical differing from hydrogen,

and at least two of the radicals R¹ to R⁹ may be part of a ring

The present invention furthermore relates to a process for thepreparation of these fuel or lubricant additives, in which apoly-1-alkene derived from one or more 1-alkenes of 3 to 24, preferably3 to 10 and particularly preferably 3 to 6, carbon atoms and from 0 to50% by weight of ethene is reacted in the presence of a free radicalinitiator under free radical-forming conditions with a) a compound ofthe general formula I and/or b) a compound of the general formula II,and to their use in fuel or lubricant compositions, in particular forinternal combustion engines.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In a preferred embodiment of the invention, the ethylenicallyunsaturated poly-1-alkenes used are poly- or oligoolefins having anumber average molecular weight of from 100 to 15,0000, obtained fromone or more 1-alkenes of 3 to 24 carbon atoms and from 0 to 50% byweight of ethene. Particularly preferred amongst these arepolyisobutenes having a number average molecular weight of from 150 to5,000, in particular from 250 to 1,000, which are derived from isobuteneand from 0 to 30% by weight of n-butene and are obtainable, for example,according to DE-A-27 02 604.

In a further preferred embodiment, poly-1-alkenes having a terminaldouble bond content of at least 95%, preferably at least 98%, are used,as obtained, for example, by polymerization or oligomerization of themonomer building blocks in the presence of a metallocene catalyst.

The poly-1-alkenes used according to the invention and derived from oneor more 1-alkenes of 3 to 24 carbon atoms and from 0 to 50% by weight ofethene, preferably poly-1-n-alkenes, can be prepared, for example, bypolymerizing 1-alkenes, preferably 1-n-alkenes, in the presence of ametallocene catalyst of the general formula III

    Cp.sub.m MX.sub.n Y.sub.r                                  III,

where Cp is an unsubstituted cyclopentadienyl unit and/or a mono-C₁ -C₄-alkylcyclopentadienyl unit, m is a zirconium or hafnium atom and theligands X are hydride and/or halogen ions and/or methyl, and in thepresence of an organoaluminum compound, preferably an alumoxane, as acocatalyst, the catalyst being used, relative to the alumoxanecocatalyst, in a ratio which corresponds to an M/Al atomic ratio of from1:250 to 1:1000 and temperatures of from 50 to 110° C. and a pressure offrom 30 to 100 bar being employed.

The catalysts III are zirconocenes and hafnocenes, including complexesof tetravalent zirconium and hafnium, in which the metal atom M isbonded in a sandwich-like manner between two unsubstituted and/or C₁ -C₄-monoalkyl-substituted cyclopentadienyl groups Cp, the remainingvalencies of the central atom M being saturated by hydride and/orhalogen ions and/or by methyl groups. Zirconocene and hafnocenecatalysts which are particularly preferably used in the novel processare those whose cyclopentadienyl groups are unsubstituted. Fluorine,chlorine, bromine and/or iodine ions may be bonded as halogen ions tothe metal atom.

Examples of suitable catalysts are:

Cp₂ ZrF₂, Cp₂ ZrCl₂, Cp₂ ZrCl₂, Cp₂ ZrI₂, Cp₂ ZrCl, Cp₂ Zr(CH₃)Cl, Cp₂Zr(CH₃)₂, Cp₂ HfF₂, Cp₂ HfCl₂, Cp₂ HfBr₂, Cp₂ HfI₂, Cp₂ HfHCl Cp₂Hf(CH₃)Cl, Cp₂ Hf(CH₃)₂.

Advantageously, only one catalyst is used in the oligomerization, but itis also possible to use mixtures of different catalysts. Preferredligands X are chloride, hydride and methyl, and zirconium isparticularly preferred as the central atom M for the catalysts III.Zirconocene chloride of the formula Cp₂ ZrCl₂ whose cyclopentadienylgroups are unsubstituted is particularly preferably used as a catalyst.

The catalysts can be synthesized in a simple manner by known methods,for example according to Brauer (editor), Handbuch der PraparativenAnorganischen Chemie, Volume 2, 3rd edition, pages 1395 to 1397, Enke,Stuttgart 1978.

The cocatalysts used are organoaluminum compounds, preferablyalumoxanes. Alumoxanes are formed in the partial hydrolysis oforganoaluminum compounds, for example those of the general formulaeAlR₃, AlR₂ Y and Al₂ R₃ Y₃, where R may be, for example, C₁ -C₁₀ -alkyl,preferably C₁ -C₅ -alkyl, C₃ -C₁₀ -cycloalkyl, C₇ -C₁₂ -aralkyl oralkaryl and/or phenyl or naphthyl and Y may be hydrogen, halogen orpreferably chlorine or bromine, or C₁ -C₁₀ -alkoxy, preferably methoxyor ethoxy. The partial hydrolysis of such organoaluminum compounds canbe carried out by various methods, for example by the method of DE-A-3240 383 or by that in EP-A-0 268 214. The resulting oxygen-containingalumoxanes are in general not uniform compounds but oligomer mixtures ofthe general formula IV ##STR3## where as a rule n is from 6 to 20 and Rhas the abovementioned meanings. If organoaluminum compounds havingdifferent radicals R or mixtures of organoaluminum compounds havingdifferent radicals R are hydrolyzed, alumoxanes having differentradicals R are formed and likewise be used as a cocatalyst.Advantageously, however, alumoxanes are used at cocatalysts. A preferredalumoxane is methylalumoxane. Since, owing to their method ofpreparation, the alumoxanes preferably used as cocatalysts are notuniform compounds, the molarity of alumoxane solutions is based below ontheir aluminum content.

For the polymerization, the catalyst is used relative to the cocatalystin an amount which corresponds to an M/Al atomic ratio of in generalfrom 1:250 to 1:1000, preferably from 1:300 to 1:600, in particular from1:400 to 1:500.

The polymerization of the 1-alkene is advantageously carried out in theliquid phase, advantageously using small amounts of a solvent,preferably of an aliphatic or aromatic hydrocarbon, such as benzene,toluene, xylene, ethylbenzene, cumene, naphthalene, tetralin, hexane,heptane, octane, isooctane, nonane, decane, dodecane, cyclohexane,decalin, petroleum ether or naphtha Particularly preferably usedsolvents are toluene and xylene. In this process, solvent/1-alkenevolume ratios of in general from 1:20 to 1:500, preferably from 1:30 to1:200, particularly preferably from 1:40 to 1:100, are established, thevolume of the 1-alkene being based on its volume at the pressure used ineach case. Under the conditions used, the 1-alkene is liquid. Thepolymerization is carried out in general at from 50 to 110° C.,particularly preferably from 60 to 90° C., and at from 30 to 100,preferably from 30 to 50, bar. The metallocene/1-alkene ratio is as arule not critical for the process, but advantageouslymetallocene/1-alkene molar ratios of from 1:50 to 1:250,000, preferablyfrom 1:70 to 1:200,000, in particular from 1:90 to 1:190,000, are used.

The polymerization may be carried out either batchwise, for example instirred autoclaves, or continuously, for example in tubular reactorsAfter the catalyst has been separated off by distillation of theproducts or by hydrolysis thereof and subsequent filtration of theprecipitated solids, the reaction mixture is advantageously worked up bydistillation, if desired at reduced pressure.

The propene preferably used as a raw material in this process mayoriginate from a variety of sources, eg. from crack gases, for examplefrom steam crackers. Propene as formed, for example, in propanedehydrogenation may also be used. Propene may be used in purified form,but it may also be used in mixtures with other hydrocarbons which areinert under the conditions of the reaction.

The polymerization process permits the selective preparation ofpoly-1-alkenes having terminal double bonds, in particular the selectivepreparation of propene polymers with high productivities.

The poly-1-alkenes used according to the invention, in particular thecopolymers of ethene and 1-n-alkenes, can also be prepared by otherknown methods, as described, for example, in EP-A-0 441 548. Here too, ametallocene catalyst is used in combination with an aluminoxane. Themetallocenes used here are likewise cyclopentadienyl-transition metalcompounds of the formula III, preferred transition metals being Ti, Zrand Hf.

The poly-1-alkenes which can be prepared in this manner may subsequentlybe further reacted in a manner known per se in the novel process, ifnecessary after prior distillation.

For the preparation of the novel additives, the poly-1-alkenes aregenerally reacted at from 0 to 200° C. in the presence of a free radicalinitiator with the compounds of the general formula I and/or II.

These compounds have, at least at one point in the molecular skeleton,at least one hydrogen atom which is readily extractable with formationof a free radical intermediate, so that an addition reaction of thesecompounds takes place at the one or more ethylenic double bonds of thepoly-1-alkene. According to the invention, preferred compounds of theformula I and/or II are those in which at least one of the substituentsR⁴ and R⁵ and/or at least one of the substituents R⁶ and R⁷ is nothydrogen. Free radical initiators, the production of free radicals andfree radical addition reactions with ethylenically unsaturated compoundsare known per se. Such free radical addition reactions are described,for example, in the following publications:

H.-H. Vogel, Synthesis 1970, page 99 et seq.;

D. Elad, Chemistry and Industry 24 (1962), 362;

Friedmann, Lester, Tetrahedron Letters 1961, 238 et seq.;

Nikishin, Vinogradov, Fedorova, J.C.S. Chem. Commun. 1973, 693;

M. Regitz, B. Giese in Houben-Weyl, Methoden der Organischen Chemie, 4thedition, Vol. E 19a (1989).

The reaction conditions in the reaction of the novel poly-1-alkenes withthe compounds of the formula I and/or II vary depending on the startingmaterials used and on the method for producing free radicals. However,the reaction temperature is in general from 0 to 200° C.

The reaction may be carried out in the absence of a solvent or with theuse of inert solvents, for example aliphatic or aromatic hydrocarbons.

The molar ratio of poly-1-alkene to compounds of the formula I and/or IIis as a rule from 1:1 to 1:30. Complete conversion of the ethylenicdouble bonds of the poly-1-alkene is, however, not necessary. Incompleteconversion may under certain circumstances even be advantageous.

The preparation of the novel additives is carried out, for example, by amethod in which about two thirds of the compound of the formula I and/orII, possibly in a suitable solvent, are initially taken at the desiredreaction temperature in a multineck flask advantageously equipped with astirrer, an internal thermometer, a reflux condenser and a droppingfunnel, and a mixture of poly-1-alkene, initiator and the remainingamount of the compound of the formula I and/or II, possibly with the useof an inert solvent, is then slowly added dropwise while stirring. Afterthe end of the addition, the reaction mixture is, if required, furtherstirred at the selected temperature to complete the reaction. The courseof the reaction can be monitored by IR spectroscopy with observation ofthe characteristic absorption band of the terminal double bond at about890 cm⁻¹. After removal of the solvent and of the excess of the compoundof the formula I and/or II, the reaction products are generally obtainedin the form of a viscous, colorless to amber residue.

In fuel compositions, in particular for internal combustion engines, thenovel additive is preferably used in an amount of from 10 to 5,000 ppm,in particular from 100 to 2,000 ppm.

In lubricant compositions, the novel additive is preferably used in anamount of from 0.5 to 10, in particular from 1 to 3, % by weight, basedon the total weight of the composition.

As a result of their preparation, the additives used in the novel fuelsor lubricants contain no halogen, which makes them particularly suitablefor use in fuels or lubricants.

Owing to their structure, the novel additives can act both asdispersants and as detergents. This means that, as detergents, they keepvalves and carburettors or injection systems clean. As dispersants, theyalso improve the dispersing of sludge in the engine oil after they haveentered the lubricant circulation of the engine via the combustionchamber.

If it is intended primarily to make use of the dispersing properties ofthe novel additives, they may also be combined with conventionaldetergents as further additives.

Products which may be used as detergent components in the mixture withthe novel substances as dispersants are in principle any known productsuitable for this purpose, as described, for example, in J. Falbe, U.Hasserodt, Katalysatoren, Tenside und Mineraloladditive, G. ThiemeVerlag, Stuttgart 1978, page 221 et seq., or in K. Owen, Gasoline andDiesel Fuel Additives, John Wiley & Sons, 1989, page 23 et seq.

N-containing detergents, for example compounds which contain an amino oramido group, are preferably used. Polyisobutylamines according to EP-A-0244 616, ethylenediaminetetraacetamides and/orethylenediaminetetraacetimides according to EP-A-0 188 786 orpolyetheramines according to EP-A-0 244 725 are particularly suitable,reference being made to the definitions in these publications. As aresult of their preparation, the products described there likewise havethe advantage of being chlorine- and chloride-free.

If it is intended primarily to make use of the detergent action of thenovel compounds, these substances may also be combined with carrieroils. Such carrier oils are known. Particularly suitable carrier oilsare those based on polyglycol, for example corresponding ethers and/oresters, as described in U.S. Pat. No. 5,004,478 or DE-A-38 38 918.Polyoxyalkylene monools having terminal hydrocarbon groups (U.S. Pat.No. 4,877,416) or carrier oils as disclosed in DE-A-41 42 241 may alsobe used.

Leaded and in particular unleaded regular and premium graded gasolinesare suitable as fuels for gasoline engines. The gasolines may alsocontain components other than hydrocarbons, for example alcohols, suchas methanol, ethanol or tert-butanol, and ethers, eg. methyl tert-butylether. In addition to the novel additives, the fuels also contain, as arule, further additives, such as corrosion inhibitors, stabilizers,antioxidants and/or further detergents.

Corrosion inhibitors are generally ammonium salts of organic carboxylicacids which, when the starting compounds have an appropriate structure,tend to form films. Amines for reducing the pH are also frequentlypresent in corrosion inhibitors. Heterocyclic aromatics are generallyused for preventing corrosion of nonferrous metals.

EXAMPLES 1. Preparation of the Novel Additives Example 1

290 g of morpholine were initially taken and heated to refluxtemperature (about 130° C.) in a multineck flask equipped with astirrer, an internal thermometer, a reflux condenser and a droppingfunnel. A mixture of the initiator di-tert-butyl peroxide (5.3 g), 500 gof polyisobutene (number average molecular weight 1,000) and 145.8 g ofmorpholine was then slowly added dropwise. After the end of the dropwiseaddition, stirring was continued for a total of 12 hours at 130° C., atotal of 5.3 g of di-tert-butyl peroxide being added a little at a timeduring this period. The reaction mixture was then freed from excessreagent.

Examples 2 to 7

The procedure was as in Example 1, but with the use of the amounts,stated in Table 1, of different compounds of the general formula I or IIand initiator. Furthermore, the mixture was heated in each case to thetemperature stated in Table 1 and this temperature was maintained duringthe reaction and the subsequent stirring.

                  TABLE 1    ______________________________________    Ex.               Compounds I or II                                     Initiator                                           Temp.    No.   Olefin (mol)                      (mol)          (mol)  ° C.!    ______________________________________    1     Polyisobutene (1)                      Diethyl malonate (10)                                     0.1   140    2     Polyisobutene (1)                      Isobutyraldehyde (2.5)                                     0.25  160    3     Polyisobutene (1)                      Pyrrolidone (10)                                     0.1   140    4     Polyisobutene (1)                      Morpholine (10)                                     0.2   130    5     Polyisobutene (1)                      Dimethylformamide (5)                                     0.5   145    6     Polyisobutene (1)                      Cyclopentanone (2.5)                                     0.25  160    7     Polyisobutene (1)                      Allylamine (2.5)                                     0.1    75    ______________________________________

The action of the derivatives prepared as valve cleaners was tested inengine tests.

2. Engine Tests

The engine tests were carried out in a 1.2 1 Opel Kadett engineaccording to CEC F/04/A/87. Fuel used: European unleaded premium grade.

                  TABLE 2    ______________________________________    Additive Dose    Intake valve deposits  mg!*    from Example              ppm!   Valves  1     2     3     4    ______________________________________    1        800             11    8     8     17                             (542) (441) (405) (623)    2        800             10    6                             (447) (262)    3        800             2     1     2     1                             (255) (155) (150) (395)    4        800             0     1     0     0                             (255) (155) (150) (395)    5        800             2     3     2     4                             (255) (155) (150) (395)    6        800             0     0     2     2                             (300) (168) (175) (355)    7        800             12    2     6     2                             (300) (300) (300) (355)    ______________________________________     *Values in brackets: Deposits without the introduction of additives; the     different values are due to differences in the European unleaded premium     grade used.

We claim:
 1. A process for the preparation of a fuel additive,comprising reacting an ethylenically unsaturated poly-1-alkene derivedfrom one or more 1-alkenes of 3 to 24 carbon atoms and from 0 to 50% byweight of ethylene in the presence of a free radical initiator underfree radical-forming conditions witha) a compound of the formula I##STR4## or b) a compound of the formula II ##STR5## where X is O orNR⁷,R¹⁰ is CN, COOH, C(O)R⁹, C(O)O(O)CR⁶, CONR⁶ R⁷, C(O)R⁹, C(S)R⁹, CHO,CH(NR⁶ R⁷)R⁶, SCR⁶ R⁷ R⁸ or OR⁶, R² and R³ are identical or differentand are each R¹, hydrogen or an organic radical differing therefrom, R⁴and R⁵ are identical or different and are each hydrogen, OR⁹, NR⁷ R⁸ oran unsubstituted or substituted (cyclo)alkyl radical or aryl radical,R⁶, R⁷ and R⁸ are identical or different and are each hydrogen or anorganic radical and R⁹ is an organic radical differing from hydrogen,and at least two of the radicals R¹ to R⁹ may be part of a ring.
 2. Theprocess as claimed in claim 1, wherein the poly-1-alkene has a numberaverage molecular weigh to from 150 to 5,000.
 3. The process as claimedin claim 1, wherein at least one of the substituents R⁴ sand R⁵ is nothydrogen.
 4. The process as claimed in claim 1, wherein at least one ofthe substituents R⁶ and R⁷ is not hydrogen.
 5. The process as claimed inclaim 1, wherein said ethylenically unsaturated poly-1-alkene ispolyisobutene and said compound of formula I is morpholine.